The invention relates to a safety valve having a valve housing, in the housing interior of which is provided a shut-off body, which is held by at least one resilient retaining element against the force of a medium traversing through the valve housing in an open position of the safety valve.
WO 2011/136999A1 describes a pressure control valve having a valve housing, in the interior of which a shut-off body is provided, which is held by a resilient retaining element against the force of a fluid traversing through the valve housing in an open position. The shut-off body is displaceable inside the valve housing in such a manner that, in the event of a pressure drop on its outflow side, said shut-off body is moved against a closing body into a closed position of the pressure control valve.
U.S. Pat. No. 4,195,658 A discloses a safety valve for preventing a gas escaping from a closed system. The safety valve comprises a piston-like plug with a head at one end and a bar-shaped body at the other end, and a housing with an inlet chamber which is dimensioned such that the plug is able to enter into the inlet chamber, as a result of which the flow of the gas through an outlet chamber is prevented. If a pressure drop occurs, for example following a pipe fracture, the safety valve is closed by means of a spring force generated by a spring element such that no gas is able to exit from the broken pipe.
Such safety valves regularly serve for automatically shutting-off a pipe which is traversable by a medium, in particular water. The term pipe, in this case, in the sense according to the invention, means any element consisting of an arbitrary form and from arbitrary material, through which a medium, in particular a fluid, for example water, is able to be conducted. Such an element that is intended for conducting through a fluid can be a hose, a tube or a pipeline or a component part of a hose, a tube or a pipeline—a fitting or a valve, for example an angle valve, can also be meant.
These types of safety valves for automatically shutting-off traversable pipes are known from the prior art and are used, for example, in the sanitary sector for the purpose of preventing damage caused by escaping water. In this case, this can be the leaking of pipes, but also completely interrupted pipes, such as, for example, in the case when a hose bursts.
Such safety valves are usually connected to hoses, tubes or pipelines at least in the sanitary sector and serve for the purpose of interrupting the flow of a fluid, for example, of water, as soon as the volume flow of the fluid through the valve has exceeded a certain value. A shut-off body, which regularly acts against the force of the traversing fluid by means of a spring, is usually provided in the interior of such valves for this purpose, the force, which acts against the fluid, being determinable by the spring constant of the spring used and consequently also being variable. The safety valves known from the prior art for automatically shutting-off pipes usually comprise a suitable element, for example a plunger, against which the shut-off body rests when the volume flow is exceeded and consequently enables the fluid pipe to be closed.
In the event of the pipes being completely or even only partially interrupted, a pressure difference is realized with reference to the regions above and below the shut-off body and the safety valve thus performs a shut-off, as a result of which the further escaping of the medium out of the pipe is stopped and damage produced by uncontrolled escaping of the medium is prevented. The safety valves known from the prior art also function according to this principle; after the triggering, i.e. the shutting-off by the safety valve, a pressure equalization must be effected so that, once the pipe that was completely or partially interrupted beforehand has been restored, the regular flow of the medium is able to be effected.
It is also known that such safety valves are also able to be triggered without a generated pressure difference, i.e. also without exceeding the volume flow. This applies in particular in the case of initial installations or other work on the pipe system where air ingress is able to cause a triggering of the safety valve although the pipe in question is intact.
In order to generate this pressure equalization, the disadvantage of the safety valves known from the prior art, however, is that the pressure equalization has usually to be effected by ventilating the safety valve, usually in relation to the atmospheric pressure present. To this end, the safety valve has to be removed from the existing pipe network to which it is connected and then once the pressure equalization has been effected has to be reconnected. A further disadvantage in this connection is that corresponding tools are required for disconnection and connection of such safety valves and consequently a not inconsiderable time expenditure. Additional time expenditure means in the case of the previously known safety valves that in addition the inflow-side valve, which can be provided, for example, as an angle valve, has to be closed prior to disconnection in order to prevent the uncontrolled escape of the medium and then has to be opened again after reconnection.
It is additionally also possible for disconnection and connection only to be able to be carried out by suitable specialist persons, as a result of which not inconsiderable costs can be generated for the end consumer. Disconnection and connection can also represent physical danger to the end consumer due to the increased pressure if there is any mishandling. The safety valves known from the prior art additionally comprise the disadvantageous development that in the event of an abrupt change in pressure, i.e. the pipe being shut off abruptly, the shut-off body used for shutting off experiences a pulse, which opposes the direction of flow of the medium, in such a manner against the element which works the shut-off body, consequently ensures the closing procedure and can be realized for example as a plunger, such that closure is not completely guaranteed at least in the short-term, and consequently in spite of the partially or completely interrupted pipe, medium is able to escape from the shut-off valve and consequently sometimes cause damage.